Contraceptive methods for men and women are important for worldwide reproductive health.
However, no effective and efficient methods of male contraception are as of yet available.
Male contraception seeks to suppress spermatogenesis through the suppression of the gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This results in a depletion of intratesticular testosterone and cessation of spermatogenesis.
Administration of progestagen results in a dose dependent suppression of pituitary gonadotrophins and consequently, a decrease in testosterone levels and a reversible inhibition of spermatogenesis. An exogenous androgen. is required to compensate for the reduced testosterone levels. In the same way, male HRT can be accomplished, resulting in replacement of testosterone by an exogenous androgen which is safer on the prostate than endogenous testosterone.
The use of progestogens together with androgens for use as male contraceptives is known (Guerin and Rollet (1988), International Journal of Andrology 11, 187-199).
However, the use of specific esters of etonogestrel for male contraception and male HRT has not been suggested.
In addition, the use of progestogens together with estrogens for use in female contraception is known (M. Tausk, J. H. H. Thijssen, Tj. B. van Wimersma Greidanus, “Pharmakologie der Hormone”, Georg Thieme Verlag, Stuttgart, 1986).
Progestagens are widely used for female contraception and in female HRT. In contraception, the combination progestagen-estrogen oral contraceptives are the most widely used. Administration of such a combination results in a number of effects: it blocks ovulation, it interferes with phasic development of the endometrium which decreases the chance for successful implantation, and it causes the cervical mucus to become so viscous that it hinders sperm penetration. Most progestagen-only-pills (POP's) aim at the last mentioned effect only.
Female HRT is aimed at suppletion of endogenous estrogen for the treatment of peri- and postmenopausal complaints (hot flushes, vaginal dryness), and for prevention of symptoms of long-term estrogen deficiency. The latter include osteoporosis, coronary artery disease, urogenital incontinence, and possibly also Alzheimer's disease and colorectal cancer. A drawback of long-tenn unopposed estrogen administration is the associated increase in endometrium proliferation, which in turn may increase the risk of endometrial cancer. For that reason, progestagens are co-administered in long-term regimes, because of their ability to reduce the proliferative activity of endometrial epithelium and to induce secretory conversion.
However, the use of specific esters of etonogestrel for female contraception, female HRT and treatment/prevention of gynaecological disorders has not been suggested.
The subject invention describes new esters of etonogestrel, i.e. etonogestrel decanoate, etonogestrel undecanoate, and etonogestrel dodecanoate which have surprisingly been found to have a better pharmacokinetic profile than other etonogestrel esters. These esters enable a single-dose administration of a progestogen with a long duration of action.
The subject invention provides new progestogen esters, i.e. etonogestrel decanoate, etonogestrel undecanoate, and etonogestrel dodecanoate and uses thereof for both male and female contraception and male and female HRT.
In addition, the use of these esters for treatment and prevention of female gynaecological disorders such as endometriosis, menorrhagia, meno-metrorrhagia, pre-menstrual syndrome and dysmenorrhoea are also contemplated.